Process for the synthetic manufacture of hydrocarbon oils



March 3,

Natural Gas J Nalural Gas DESULPHURIZER M. STEINSCHLAEGER PROCESS FORTHE SYNTHETIC MANUFACTURE OF HYDROCARBON OILS Filed July 15, 1947 1FIG.I.

CRACKING REACTOR H 20 3/ ABSORBER Tg' 2 3f 25; l 00 REMOVAL. M SlcainREAc'roR J/ Jr) J2 Llquld ABSORBER HQ N 7 .1;

J l J CO3 REMOVAL J8 Slsam 6 0 4 4 2 REA cToR Liquid ABSOR BER 4 9 G02REMOVAL 1/3 Residual Gas Natural Gas Heal Exch.

g/ F I e. 2. DESULPHURIZER {I J1 IF l- Hsai Exch.

. REACTOR ABSOR ER A c0: REMOVAL I 5 g mm 1 I Slearr W a REACTOR m Liuld ABsoRBER .6. 7a 74 00 REMOVAL 79 Steam 867 HEATER 82 REACTOR 84Liquid ABSORBER "-6.

co REMOVAL q Sisam REAcToR 96 ABSOR B E R Liquid 0O REMOVAL M/ /03')Residual Gas v INVENTOR" MICHAEL STEINSCHLAEGER ATTORNEYS Patented Mar.3, 1953 PROCESS FOR THE SYNTHETIC MANUFAC- TURE OF HYDROCARBON OILSMichael Steinschlaeger, London, England Application July 15, 1947,Serial No. 761,022 In Great Britain September 3, 1942 2 Claims. 1

This invention relates to a process for the manufacture of hydrocarbonoils and is particularly concerned with the production of products richin olefines.

Primary products obtained by the Fischer- Tropsch or like processes fromgases containing CO and H2 in ratios varying between 1:15 and 2:1 byvolume are rich in valuable olefines. On the other hand, in order toavoid the formation and deposition of carbon on the catalyst and so todestroy or damage the activity of the same, it is necessary to maintainthe operating conditions such that the yield of primary products rich inolefines per cubic metre of gas used in comparison with the yieldsobtained in the synthesis processes using gases having a ratio of CO:H2=1 :2 by volume is low. Consequently a high consumption of fuels, highcost of production and high capital expenditure for the plant areinvolved.

The following suggestions have been made to overcome these drawbacks:

' (a) Re-cycle the residual gases and vent a part of the residual gas soas to avoid atoo high concentration of inerts such as carbon dioxide,nitrogen and methane;

(b) Separate the inerts from the residual gases before mixing them withthe original gas by removing carbon dioxide by absorption, nitrogen byliquefaction (very high cost of: 1, the operation; 2, the plant; 3, thepower consumption); and by converting methane to carbon monoxide andhydrogen;

' (c) It has been further suggested to use oxygen in the production ofsynthesis gas but as will be shown hereinafter the cost of the oxygenproduction and the cost of the plant for production of oxygen increaseconsiderably the cost per unit of primary products obtained.

The disadvantages of the prior proposals are dealt with in detailhereinafter.

An object of the present invention is to overcome these drawbacks and inaddition to provide the considerable amount of sulphur free carbondioxide required to produce carbon monoxiderich gases for example fromnatural gas according to the reaction CH4+CO2=2CO+2H2.

It has been suggested to obtain the carbon dioxide by the burning ofresidual gases (which is wasteful; it is better to convert the residualgases into primary products as far as possible) and washing out thecarbon dioxide. If other sources of carbon dioxide are used such ascombustion gases from natural gas not freed from organic and inorganicsulphur it is necessary to purify the carbon dioxide obtained from theabove 1m: purities.

To obtain primary products rich in olefines usually cobalt oriron-containing catalysts are used and the reactions involved in thesynthesis are as follows:

A. Cobalt catalyst:

Using an iron catalyst it is possible also to ob-,- tain a part of theproducts as in the cobalt reaction and consequently it is possible toregulate the amount of carbon dioxide (and the composi: tion of theresidual gases obtained in respect'of carbon monoxide and hydrogencontent) obtained according to the requirements in the process.

The present invention provides a process of producing normally liquidhydrocarbons rich in olefines by synthesis of carbon monoxide andhydrogen which comprises, in an initial synthesis gas-forming step,reacting fixed hydrocarbon gases (previously freed from sulphur andother undesirable impurities) with carbon dioxide of the residue gasproduced in the synthesis reaction to form a carbon monoxide-hydrogenmixture (synthesis gas I) containing CO and H2 in a ratio varying frombetween 111.5 and 2:1 by volume. The synthesis gas-forming reaction maybe brought about by the use of any suitable reforming catalyst andheating to a suitabletemperature. For example, the mixture of fixedhydro carbon gases and carbon dioxide may be heated at 1000 C. inthenpresence ofa nickel catalyst. The resulting synthesis gas mixture isthen caused to undergo a hydrocarbon synthesis in the presence of acatalyst selected from the group con sisting of cobalt, nickel and ironat a temperature of between and 400 C. in a first reaction zone toproduce primary products rich in olefines and a residual gas (residualgas I). The liquefiable hydrocarbons rich in olefines are then separatedfrom the residual reaction gases. At least a large part of the carbondioxide present in the residual gas is also separated and recycled tothe initial synthesis gas-forming stage. The remainder of the residualgases is then mixed with gases rich in gaseous hydrocarbons and withsteam in proportions adjusted to insure on subsequent reforming asynthesis gas containing CO and H2 in proportions within the rangepreviously stated. The resulting mixture is then subjected to acatalytic reforming as by heating at a temperature between 800 and 1500C. in the presence of a nickel catalyst thereby producing a secondsynthesis gas mixture (synthesis gas II). This second synthesis gasmixture is then caused to undergo a hydrocarbon synthesis at atemperature within the range and in the presence of a catalyst of thegroup specified for the first stage synthesis. The liquefiableolefine-rich hydrocarbons formed in the second synthesis step are thenseparated as before, and likewise at least a large part of the carbondioxide is separated and recycled to the initial synthesis gas-formingstep. The successive steps of catalytic reforming of the residual gasesfrom each preceding synthesis step with fixed hydrocarbon gases andsteam added in proportions to insure formation of fresh increments ofsynthesis gas containing carbon monoxide and hydrogen in the controlledproportions previously stated and the synthesizing of the resultingsynthesi gas to form olefine-rich mixtures, followed by separation ofthe liquefiable hydrocarbons, removal and recycling of at least part of'the'carbon dioxide, and addition of fresh increments of hydrocarbongases and of steam for the successive catalytic reforming stages, areall repeated in sequence until the inert content of the residualreaction gases has built up to the point where the yield'of liquidhydrocarbons rich in olefines has been substantially lowered so as tomake for an uneconomic operation. The final residual gases may-then beused as low grade fuel for supplying heat needed at certain stages ofthe processor for other heating purposes.

Examples of hydrocarbon-containing gases which may be used'are naturalgas and coke oven as. The composition of the synthesis gases I, II, eta,canbe varied according to the primary products which are required andaccording to the catalysts used.

Some embodiments of the process of the invention and the advantagesthereof using natural gas as the hydrocarbon-containing gas will now be.further described in the following examples in which the percentagesare by volume), and with the aid of the accompanying drawings, in which:

Fig. :1 is a flow sheet showing the manufacture of valuable productsaccording to the invention starting from natural gas, and

Fig. 2is a flow sheetshowinga modified form of the process illustratedin Fig. 1.

In thedrawings valves and other controls are omitted for thesake ofclarity.

EXAMPLE 1 Referring to Fig. 1 of the drawings, natural gas having acomposition CH4=90.0%, C2H6=8.0%, and C02+Nz='2.0% was admitted throughline I into a conventional desulphurising apparatus 2 and 250,000 cubicmetres of the purified natural gas obtained was mixed with 300,000 cubicmetres of carbon dioxide admitted through line 3, and

.line 3.

the mixture passed through line 4 into cracking apparatus 5 where it wacracked at 1000 C. in the presence of a nickel cracking catalyst toproduce a synthesis gas I having the composition CO=4=6.0%, H2=5l.0% andCH4+N2+CO2=3.0%.

1,000,000 cubic metres of the synthesis gas I was passed through line 6and subjected to a hydrocarbon synthesis treatment at C. in vessel Iwhich contained a cobalt catalyst.

The products obtained were passed via line 8 into a condensation andabsorption plant 9 where 92 metric tons of liquid hydrocarbons and Csand C4 hydrocarbons rich in olefines were condensed and removed throughline 10. The gaseous products were then passed via line I l to aconventional carbon dioxide removal plant I2 where the carbon dioxidewas removed and re-cycled via line [3 to The residual gas I which wasremoved via line H amountd to 500,000 cubic metres having a compositionof CO=56.0%, H2=32.0%, CH4+N2=12.0%, and was mixed with 50,000 cubicmetres of natural gas of the composition given above, admitted throughline [5.

After addition of 120,000 kgs. of steam admitted through line IS themixture was heated in heater I! at 1000 C. in the presence of a nickelcatalyst and the treated gas, amounting to 810,000 cubic metres(synthesis gas II) had the following composition: CO=45.5%, Hz=51.5%,and CH4+N2+CO2= .0%. The synthesis gas II was then passed by line [8 tovessel I9 which contained a cobalt catalyst and wherein the temperaturewas maintained at 180 C. The products were passed via line 20 into thecondensation and absorption plant 2| where 75 metric tons of liquidhydrocarbons and C3 and C4 hydrocarbons rich in olefines were condensedand removed through line 22. The gaseous products were then passed vialine 23 to a conventional carbon dioxide removal plant 24 where carbondioxide was removed and re-cycled via line 25 to line 3.. The residualgas II obtained after removal of the carbon dioxide amounted to 405,000cubic metres and had the following composition: CO=56.0%,, H2=32.0%, andCH4+N2=12.0%. This residual gas II was withdrawn through line 26andmixed with 45,000 cubic metres of natural gas of the compositiongiven above, admitted through line 21.

After addition of 110,000 kgm. of steam admitted through .line 28, themixture was heated in heater 29 at 1000 C. in thepresence of a nickelcatalyst and the treated gas amounting to 670,000 cubic metres(synthesis gas III) had the following composition: CO=44.8%, H2=51.8%and CH4+N2+CO2=3.4%. The synthesis gas III was then passed via line 30to vessel 3| which contained a cobalt catalyst and was subjected to ahydrocarbon synthesis treatment therein at 180 C. The products werepassed via line 32 into the condensation and absorption plant .33 where62 metric tons of liquid hydrocarbons .and C3 and C4 hydrocarbons richin olefines were condensed and removed-through line 34. The gaseousproducts were then passed via line 35 to a conventional carbon dioxideremoval plant 136 where carbon dioxide was removed and re-cycled vialine 31 to line 3. The residual gas III obtained after removal of thecarbon dioxide amounted to 335,000 cubic metres and had the followingcomposition: CO=54.0%, H2=32.0% and CH4+N2=14.0%. The residual gas IIIwas now withdrawn through line 38 and mixed with 30,000 cubic metres ofnatural gas of the composition given above admitted through line .39.

After addition of 80,000 kgs. of steam admitted through line the mixturewas heated in heater 4| at 1000 C. in the presence of a nickel cata-.lyst and the treated gas amountin to 510,000

cubic metres of this purified natural gas leaving the purifier throughline 54 was mixed with 274,000 cubic metres of carbon dioxide admittedthrough line and the mixture passed cubic metres (synthesis gas IV) hadthe follow- 5 through heat exchanger 56 into the cracking ingcomposition: C0=45.0%, H2=51.0% and apparatus 51, where it was crackedat 850 C. in CH4+N2+CO2=4.0%. The synthesis gas IV was the presence of anickel cracking catalyst to prothen passed via line 42 to vessel 43which conduce 1,000,000 cubic metres of a synthesis gas I tained acobalt catalyst and wassubjec ted to at having the composition CO=52.0%,H2=43.2%, hydrocarbon synthesis treatment therein at 10 CO2=1.8%,N2=1.6% and CH4=1.4=%, which was 180 C. The pr c s ere passed via line44 passed through line 58 and through heat exinto the condensation andabsorption plant 45 changer 59 to vessel in which it was subjected where47 metric tons of liquid hydrocarbons and to a hydrocarbon synthesistreatment at 250 C. C3 and C4 hydrocarbons rich in olefines were Thevessel 60 contained an iron catalyst. The condensed and removed throughline 46. The 15 products obtained were passed via line 6| into a gaseousproducts were then passed via line 41 to condensation and absorptionplant 62 where 92 a conventional carbon dioxide removal plant 48 metrictons of liquid hydrocarbons and C3 and where carbon dioxide was removedand re-cycled C4 hydrocarbons rich in olefines were condensed via line49 to line 3. The residual gas IV was reand removed via lines 62a. Thegaseous products m'oved via line 50 and used for heating in the 20(583,000 cubic metres) were then passed via line plant. 63 to aconventional carbon dioxide removal plant If desired, the gas leavingvessel 33 may be 84 where the carbon dioxide was removed and reactedwith steam to increase the proportion of re-cycled via line 65 to line55. The residual gas hydrogen before being passed to the plant 36 for Iwhich was removed via line 66 amounted to the removal of carbon dioxide.25 488,000 cubic metres and had the following com- The results obtainedare summarised in the position: CO=55.2%, H2=33.1%, CH4='7.0%, followingTables Iand II. N2=3.3%, CO2=1.4%. The residual gas I was Table ISynthesis Gas No 1 2 3 4 1. Production of Synthesis Gas Natural gastreated Residual gas Inatu- Residual Gas IIr1at- Residual Gas III- fr mwith CO2 in the r01 gas with steam ural gas with steam natural gas withpresence of a catain the presence of a in the presence of a steam in thepresence lyst at 1000 0. catalyst at 1000 0. catalyst at 1000 0. of acatalyst at 1000 2, Synthesis 005, cubic metres- 1,000,000 510,000. 3.Used Residual Gas, cubic 335,000.

metres. 4. Used natural gas 25 ,000 30,000. 5. Composition of Synthesis454.

Gas CO+H2%. 6. Composition of Residual Gas 0o+12r2%. 7. Yields ofprimary products 92 47 rich in oiefines (metric tons) Table II Incrts rI Cubic CH4+N+CO2 Natural gas Itesidual 533mg Synthesis Gas No. metfesused, cubic Gas, cubic obtained Cubic metres metres tons Percent metres1 I. 0. approximately 3,000,000.

Consumption of natural gas per kg. of primary products: 1. For synthesisgas production. 1.36 cubic metres. V 2. For heating purposes, 0.6i cubicmetre. Total consumption per kg. of primary products rich in olefines,2.0 cubic metres.

EXAMPLE 2 Referring now to Fig. 2 of the drawings, natural gas having acomposition CH4=70.0%, C2He=7.0%, C3Ha=10.0%, C4H1o=5.0% and N2=8.0% anda net calorific value of 10,800 cals. per cubic metre was introducedthrough line 5| into heat exchanger 52 and thence into a connow passedthrough heat exchanger 61, 40,000 kgs. of steam were admitted throughline 68 and the mixture was heated to 1000 C. in the presence of anickel catalyst in heater 69 to produce 580,000 cubic metres of gaswhich was withdrawn through line 10. The gas had the followingcomposition: CO=51.8%, H2=43.7%, .CH4=0.6%,

ventional desulphurising apparatus 53. 204,000 N2=2.7% and CO =1 2% Afurther 420,000 cubic metres of synthesis gas I made from 86,000 cubicmetres of the natural gas referred to above was mixed with the 580,000cubic metres of gas by introduction through line II to form synthesisgas II and synthesis gas II was now subjected to a hydrocarbon synthesistreatment at 250 C. in vessel 12 whichcontained an iron catalyst. Theproducts obtained were passed via line I3 into a condensation andabsorption plant M where 92 metric tons of liquid hydrocarbons and C3and C4 hydrocarbons rich in olefines were condensed and removed throughline 15. The gaseous products (583,000 cubic metres) were then passedthrough line IE to a conventional carbon dioxide removal plant I! wherethe carbon dioxide was removed and recycled via line 18 to line 55. Theresidual gas II, which was removed via line I9, amounted to 493,000cubic metres and had the following composition: CO=54.4%, H2=33.8%,CH4=5.9%, Nz=4.'7%, and CO2=1.2%. The residual gas II was now mixed with35,000 kgs. of steam admitted through line 80 and the mixture heated inheater III at 1000 C. in the presence of a nickel catalyst to produce570,000 cubic metres of gas which was withdrawn through line 82. The gasobtained had the composition: CO=51.5%, H2=43.2%, CO2=1.3%, N2=3.3% andCH4=0.7%.

A further 230,000 cubic metres of synthesis gas I made from 47,000 cubicmetres of the natural as referred to above was mixed with the gas byintroduction through line 83 to produce synthesis gas III. Synthesis gasIII was now subjected to a hydrocarbon synthesis treatment at 250 C. invessel 84 which contained an iron catalyst. The products obtained werepassed via line 85 into a condensation and absorption plant 85 where 74metric tons of liquid hydrocarbons and C3 and C4 hydrocarbons rich inolefines were condensed and removed through line 81. The gaseousproducts (460,000 cubic metres) were then passed through line 88 to aconventional carbon dioxide removal plant 89 where the carbon dioxidewas removed and re-cycled via line 90 to line 55. The residual gas IIIwhich was removed via line 9| amounted to 393,000 cubic metres and hadthe following composition: CO=53.8%, H2=32.8%, CH4=5.5%, N2=6.7% andCO2=l.2%. The residual gas III was now mixed with 26,000 kgs. of steamadmitted through line 92 and the mixture heated in heater 93 at 1000 C.in the presence of a nickel catalyst to produce 450,000 cubic metres ofgas which had the following composition: CO=51.2%, H2=42.0%, CO2=1.1%,N2=5.3% and CH4=0.5%. The gas was withdrawn through line 94 and mixedwith a further 50,000 cubic metres of synthesis gas I made from 10,000cubic metres of the natural gas referred to above, the said synthesisgas I being admitted through line 95, to form synthesis gas IV. Thesynthesis gas IV was now subjected to a hydrocarbon synthesis treatmentat 250 C. in vessel 96 which contained an iron catalyst. The productsobtained were passed via line 91 into a condensation and absorptionplant 98 where 46 metric tons of liquid hydrocarbons and C3 and C4hydrocarbons rich in olefines were condensed and removed through line99. The gaseous products were then passed through line I to aconventional carbon dioxide removal plant IOI where the carbon dioxidewas removed and re-cycled via line I02 to line 55. The residual gas IV(250,000 cubic metres) having the composition CO=53.0%, H2=30.0%,

CH4=5.1%, N2=10.7% and CO2=1.2% was removed via line I03 and used forheating in the system.

In this example the reactions with carbon dioxide which take place maybe expressed as follows:

The average reaction heat required (assuming 90% conversion of CH4 intoCO and H2) per cubic metre of the natural gas employed amounts to 2940cals.

Per cubic metre of natural gas 4.90 cubic metres of synthesis gas I ofthe following average composition have been obtained:

00 Hi CH4 N2 CO2 Percent 52.0 43.2 1.4 1.6 1.8

The total heat required to convert 1 cubic metre of natural gas into 4.9cubic metres of synthesis gas I amounts to: (Assuming that the naturalgas is heated in the presence of a catalyst to 850 C. and the naturalgas and carbon dioxide are pre-heated to 500 C.)3390 cals. per cubicmetre.

Furthermore, assuming that the mixture of natural gas and carbon dioxideis heated in regenerators or stoves which have been heated by a previousoperation by using pre-heated gases and air for combustion.

Taking the efficiency of the plant at 85%, the amount of heat requiredto produce 4.9 cubic metres of synthesis gas I will be 3390 4000 cals.

or equivalent to 0.37 cubic metre of natural gas.

The amount of carbon dioxide required per cubic metre of natural gas is1.3 cubic metres.

In the above example an iron catalyst was used and the average yield percubic metre of synthesis gas is chosen low (so as to avoid the formationand deposition of carbon on the cata1yst)-92 gms. per cubic metre(liquid hydrocarbons and C3 and C4 hydrocarbons rich in olefines).

Reactions using iron catalysts:

(2CO-i-H2) I (CO2-l-CH2) z 2CO+2H2=CH4+CO2 (1) (CO+2H2)$:(H2O+CI-Iz)CO+3H2=CH4+H2O (2) The reaction in the example:

For production of-- CH2 1.5CO+1.5H2:

0.5CO2+ HzO|-CH2 (1a) As a considerable amount of carbon dioxide isrequired in the process the reaction in the example may be varied so asto vary the amount of carbon dioxide obtained in the process.

. c The results are summarized in Tables III and IV.

hydrocarbons and wi th steam in proportions adjusted to insure onsubsequent reforming a syn- Table III Production of Synthesis gas fromNatural gas treated with C02 in presence of catalyst at 850 O.SynthesisGas I.

2. Synthesis Gas, cubic metres 1,000,000 3. Residual Gas used:

Residual Gas+OOr formed, cubic metres.

(0) After removal of 00 cubic metres. (0) After treatment with steam atelevated temperature.

4. Synthesis Gas I used, cubic metres 1,000,000 0r equivalent of NaturalGas, cubic 204,000 metres.

5. Composition of Synthesis Gas, 00+ 52.0+43.2=95.2

H2, Dercent.

6. Composition of Residual Gas after removal of CO2:

CO+HZ+CH4+N2+OO2 55.2+33.1+7.0+3.3+

7. Inert contents of the Synthesis Gas:

COz+N2+CH4, percent 1.8+1.6+1.4=4.8

8. Yields of primary products rich in ole- 92 fines, tons.

9. CO1 production according to the reac- 83,000 cubic metres.-.

tions (1) and (2).

10. CO; removed from Residual Gases, 95,000

cubic metres.

Residual Gas I treated with steam in presence of catalyst at ResidualGas II treated with steam in presence of catalyst Residual Gas IIItreated with steam at elevated temp.-

850 C.-Synthesis at 850 O.Synthe- Synthesis Gas I, Gas I, Synthesis sisGas 1, Synthesis Synthesis Gas IV. Gas II. Gas III.

Total amount of natural gas used for synthesis and freed from sulphurcompounds=347,000 cubic metres;

Primary products=304 tons; CO removed=285,000 cubic metres;

Natural gas used for heating after deducting the heating value of theresidual gas=0.34 cubic metre per kgm.; Total amount of natural gas usedper kgm. of primary products rich in olelines=1.48 cubic metres.

==l.14 cubic metres (or 5,000 cu. ft. per barrel oi oil);

Table IV Inerts Cubic metres Natural Residual GO: cb- Primary SynthesisGas No. ifi gfg fi igg tained, cuproducts,

cot-m, on. CO2+N2 on. metres 00. metres 139,000X100 170,400Xl00 O 02 N2W4.2%, 0 05 Na CH; 5.2%

This application is a continuation-in-part of my application Serial No.492,949, filed June 30, 1943, now abandoned, and is related to my 00-pending patent application Serial No. 322,603, filed November 26, 1952,which is directed in part to matter disclosed but not claimed herein.

I claim:

1. A process of producing normally liquid hydrocarbons rich in olefinesby synthesis of carbon monoxide and hydrogen which comprises, in aninitial gas-forming stage, reacting fixed hydrocarbon gases with carbondioxide of residue gas produced in the process to form a carbonmonoxide-hydrogen mixture containing CO and H2 in a ratio varyingbetween 1:15 and 2:1 by volume, synthesizing said mixture in thepresence of a catalyst selected from the group consisting of cobalt,nickel and iron at a temperature of between 150 and 400 C., separatingthe liquefiable olefine-rich hydrocarbons from the residual reactiongases, separating at least a large part of the carbon dioxide present insaid residual gases and recycling same to the initial synthesisgas-forming stage, mixing the remainder of said residual reaction gaseswith gases rich in gaseous thesis gas containing CO and H2 inproportions within the range previously stated, subjecting the resultingadmixture to catalytic reforming to produce a, second synthesis gasmixture of the controlled carbon monoxide-hydrogen ratio above stated,and synthesizing said second synthesis gas mixture at a temperaturewithin the range and in the presence of a catalyst of the groupspecified for the first stage synthesis.

2. A process of producin normally liquid hydrocarbons rich in olefinesby synthesis of carbon monoxide and hydrogen which comprises, in aninitial gas-forming stage, reacting fixed hydrocarbon gases With carbondioxide of residue gas produced in the process to form a carbonmonoxide-hydrogen mixture containing C0 and H2 in a ratio varyingbetween 1:15 and 2:1 by volume, synthesizing said mixture in thepresence of a catalyst selected from the group consisting of cobalt,nickel and iron at a temperature of between and 400 0., separating theliquefiable olefine-rich hydrocarbons from the residual reaction gases,separating at least a large part of the carbon dioxide present in saidresidual gases and recycling same to the initial synthesis gasformingstage, mixing the remainder of said residual reaction gases with gasesrich in gaseous hydrocarbons and with steam in proportions adjusted toinsure on subsequent reforming a synthesis gas containing and H2 inproportions within the range previously stated, subjecting the resultingadmixture to catalytic reforming to produce a second synthesis gasmixture of the controlled carbon monoxide-hydrogen ratio above stated,synthesizing said second synthesis gas mixture at a temperature withinthe range and in the presence of a catalyst of. the group specifled forthe first stage synthesis, then separating the liquefiable olefine-richhydrocarbons formed in the second synthesis step and thereafterrepeating in successive stages the catalytic reforming treatment of theresidual gases from each preceding synthesis step with fixed hydrocarbongases and steam added in proportions adjusted to insure formation offresh increments of synthesis gas containing carbon monoxide andhydrogen in the controlled proportions previously stated andsynthesizing the resulting synthesis gas to form olefine-rich mixturesof liquid hydrocarbons and residual reaction gases, and intermediateeach synthesis step and the succeedin reforming step separating thecarbon dioxide formed in the synthesis and recycling same to the initialsynthesis gas-forming stage of the process, said successive carbondioxide recycling, synthesis gas reforming and hydrocarbon synthesissteps being repeated until the inert content of the residual reactiongases has built up to the point Where the yield of olefine-rich liquidhydrocarbons is substantially lowered.

MICHAEL STEINSCHLAEGER.

REFERENCES CITED The following references are. of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,149,515 Fischer Mar. 7, 19392,220,357 Steinschlaeger Nov. 5, 1940 2,234,941 Keith, Jr Mar. 11, 19412,286,814 Kemp June 16, 1942 2,274,064 Howard et a1. Feb. 24, 19422,499,372 DOuville Mar. 7, 1950

1. A PROCESS OF PRODUCING NORMALLY LIQUID HYDROCARBONS RICH IN OLEFINESBY SYNTHESIS OF CARBON MONOXIDE AND HYDROGEN WHICH COMPRISES, IN ANINITIAL GAS-FORMING STAGE, REACTING FIXED HYDROCARBON GASES WITH CARBONDIOXIDE OF RESIDUE GAS PRODUCED IN THE PROCESS TO FORM A CARBONMONOXIDE-HYDROGEN MIXTURE CONTAINING CO AND H2 IN A RATIO VARYINGBETWEEN 1:1.5 AND 2:1 BY VOLUME, SYNTHESIZING SAID MIXTURE IN THEPRESENCE OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF COBALT,NICKEL AND IRON AT A TEMPERATURE OF BETWEEN 150 AND 400* C., SEPARATINGTHE LIQUEFIABLE OLEFINE-RICH HYDROCARBONS FROM THE RESIDUAL REACTIONGASES, SEPARATING AT LEAST A LARGE PART OF THE CARBON DIOXIDE PRESENT INSAID RESIDUAL GASES AND RECYCLING SAME TO THE INITIAL SYNTHESISGAS-FORMING STAGE, MIXING THE REMAINDER OF SAID RESIDUAL REACTION GASESWITH GASES RICH IN GASEOUS HYDROCARBONS AND WITH STEAM IN PROPORTIONSADJUSTED TO INSURE ON SUBSEQUENT REFORMING A SYNTHESIS GAS CONTAINING COAND H2 IN PROPORTIONS WITHIN THE RANGE OF PREVIOUSLY STATED, SUBJECTINGTHE RESULTING ADMIXTURE TO CATALYTIC REFORMING TO PRODUCE A SECONDSYNTHESIS GAS MIXTURE OF THE CONTROLLED CARBON MONOXIDE-HYDROGEN RATIOABOVE STATED, AND SYNTHESIZING SAID SECOND SYNTHESIS GAS MIXTURE AT ATEMPERATURE WITHIN THE RANGE AND IN THE PRESENCE OF A CATALYST OF THEGROUP SPECIFIED FOR THE FIRST STAGE SYNTHESIS.